The reason being is that zb is only 32 bit program, the so called 64 bit zbrush is a myth. so you can chuck all you like at it, it just falls after a while anyway. We managed a 17million poly model on a forced 3gb of ram at Redvision, but even with quad core and a good card it fell to its knees after a bit. Roll on Z4!! But as I said before Mudbox was worse on 64!!

Jay